One method of detecting the location of an object is use of a conventional Global Positioning Systems (GPS). In general, a conventional GPS system includes a constellation of twenty-four or more GPS satellites that orbit the earth. Each GPS satellite continually transmits, from space to earth, specially encoded GPS satellite signals (i.e., RF or Radio Frequency signals) that corresponding GPS receiver devices receive and process to determine location. According to a specific orbital arrangement of the GPS satellites around the earth, a GPS receiver device positioned in the air or on the surface of the earth receives between five and eight different GPS satellite signals from respective orbiting GPS satellites. Based on processing of four or more GPS satellite signals using certain GPS navigation algorithms (e.g., algorithms that measure of code-phased arrival times of four different received RF signals), a GPS receiver device can compute or estimate the location of the GPS device in three dimensions (e.g., altitude, latitude and longitude or X, Y and Z). Based on tracking the location of the GPS receiver device over time, the velocity of the GPS device can be determined.
Navigation in three dimensions is a primary function of most conventional GPS systems. Consequently, GPS location tracking devices are widely used in position-detecting systems for aircraft, ships, ground vehicles, as well as handheld devices carried by individuals.